CA2946942A1 - Method for releasing the rotor poles in an electrical machine - Google Patents
Method for releasing the rotor poles in an electrical machine Download PDFInfo
- Publication number
- CA2946942A1 CA2946942A1 CA2946942A CA2946942A CA2946942A1 CA 2946942 A1 CA2946942 A1 CA 2946942A1 CA 2946942 A CA2946942 A CA 2946942A CA 2946942 A CA2946942 A CA 2946942A CA 2946942 A1 CA2946942 A1 CA 2946942A1
- Authority
- CA
- Canada
- Prior art keywords
- carrier plate
- rotor
- gas
- pole
- stator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/0006—Disassembling, repairing or modifying dynamo-electric machines
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
- H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
- H02K15/022—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies with salient poles or claw-shaped poles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49009—Dynamoelectric machine
- Y10T29/49012—Rotor
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49718—Repairing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49718—Repairing
- Y10T29/49721—Repairing with disassembling
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Power Engineering (AREA)
- Manufacture Of Motors, Generators (AREA)
Abstract
The invention relates to a device for detaching a rotor pole of a large electric machine from the rotor hub, which, when mounted, is located within the stator, said device consisting of a carrier plate (1) and at least one cushion (2) which can be filled with gas and is fastened to the carrier plate.
Description
Device and method for releasing the rotor poles in an electrical machine The present invention relates to a device and a method for removing the rotor poles in a large electrical machine, as is used for example in hydroelectric power plants.
For servicing and maintaining or for reconditioning or modernizing a large electrical machine, it may be necessary to remove the rotor poles. In order to keep the effort and costs involved in this measure down as much as possible, the poles are generally pulled out of the rotor hub in an axial direction, the rotor hub remaining in the electrical machine. It occasionally happens that the removal of the rotor pole presents unexpected difficulties. The object of the present invention is to overcome these difficulties in a way which on the one hand does not cause any damage to the electrical machine and on the other hand is as inexpensive as possible.
The rotor poles are usually mounted on the rotor hub with the aid of dovetail or hammerhead connections. During operation, the poles are subjected to the centrifugal force that acts in a radial direction. The inventors have realized that the difficulties arise because the poles become twisted in the mounting in such a way that, to release this unwanted connection, it is necessary to exert on the poles a force that has to be directed in the negative radial direction, i.e. toward the rotor axis. Only once the poles have been released from the unwanted connection to the rotor hub by the action of the force directed in this way can they be pulled out in an axial direction without further difficulties. However, such a force cannot readily be exerted on the poles, since a rotor pole in the fitted state is only accessible to a restricted extent. Generally, only one or both end faces of the pole is freely accessible. A force in the negative radial direction can thus initially only act on these locations. Experience shows that this procedure is often insufficient to release the pole from the unwanted connection to the hub over its entire length.
For servicing and maintaining or for reconditioning or modernizing a large electrical machine, it may be necessary to remove the rotor poles. In order to keep the effort and costs involved in this measure down as much as possible, the poles are generally pulled out of the rotor hub in an axial direction, the rotor hub remaining in the electrical machine. It occasionally happens that the removal of the rotor pole presents unexpected difficulties. The object of the present invention is to overcome these difficulties in a way which on the one hand does not cause any damage to the electrical machine and on the other hand is as inexpensive as possible.
The rotor poles are usually mounted on the rotor hub with the aid of dovetail or hammerhead connections. During operation, the poles are subjected to the centrifugal force that acts in a radial direction. The inventors have realized that the difficulties arise because the poles become twisted in the mounting in such a way that, to release this unwanted connection, it is necessary to exert on the poles a force that has to be directed in the negative radial direction, i.e. toward the rotor axis. Only once the poles have been released from the unwanted connection to the rotor hub by the action of the force directed in this way can they be pulled out in an axial direction without further difficulties. However, such a force cannot readily be exerted on the poles, since a rotor pole in the fitted state is only accessible to a restricted extent. Generally, only one or both end faces of the pole is freely accessible. A force in the negative radial direction can thus initially only act on these locations. Experience shows that this procedure is often insufficient to release the pole from the unwanted connection to the hub over its entire length.
2 The inventors have realized that it is necessary to apply the releasing force homogeneously over the entire length of the pole.
The inventors have realized that the stated object can be achieved by a device with the characterizing features of claim 1. This device is used in a method with the characterizing features of claim x. Further advantageous refinements of the inventive solution are provided by the subclaims dependent on these.
The solution according to the invention is explained below on the basis of figures, in which specifically:
Figure 1 shows a device according to the invention in plan view;
and Figure 2 shows a device according to the invention from the front; and Figure 3 shows a method according to the invention.
In the representation of Figure 1, a device according to the invention for removing the rotor poles is shown in a schematic form. Here, a carrier plate is denoted by 1 and a cushion to be filled with gas is denoted by 2. In Figure 2, the device according to the invention can be seen from the front. In the arrangement shown, three cushions 2 to be filled with gas are located one on top of the other on the carrier plate 1. However, depending on the pole geometry, any number of cushions may be provided on a carrier plate. The device according to the invention for removing the rotor poles is in this case used in the following way: the carrier plate is introduced together with the cushions attached to it, which are not filled with gas, into the air gap between the generator stator and the rotor poles.
The air gap is generally only a few centimeters wide. When the cushions are filled with gas, they expand in such a way that they exert a force both on the stator and on the rotor pole to be released. These forces increase proportionately with =
The inventors have realized that the stated object can be achieved by a device with the characterizing features of claim 1. This device is used in a method with the characterizing features of claim x. Further advantageous refinements of the inventive solution are provided by the subclaims dependent on these.
The solution according to the invention is explained below on the basis of figures, in which specifically:
Figure 1 shows a device according to the invention in plan view;
and Figure 2 shows a device according to the invention from the front; and Figure 3 shows a method according to the invention.
In the representation of Figure 1, a device according to the invention for removing the rotor poles is shown in a schematic form. Here, a carrier plate is denoted by 1 and a cushion to be filled with gas is denoted by 2. In Figure 2, the device according to the invention can be seen from the front. In the arrangement shown, three cushions 2 to be filled with gas are located one on top of the other on the carrier plate 1. However, depending on the pole geometry, any number of cushions may be provided on a carrier plate. The device according to the invention for removing the rotor poles is in this case used in the following way: the carrier plate is introduced together with the cushions attached to it, which are not filled with gas, into the air gap between the generator stator and the rotor poles.
The air gap is generally only a few centimeters wide. When the cushions are filled with gas, they expand in such a way that they exert a force both on the stator and on the rotor pole to be released. These forces increase proportionately with =
3 increasing gas pressure inside the cushions. The force that acts on the rotor pole is the force that is necessary for releasing the pole. In order that this force can be distributed homogeneously over the entire length of the pole, the cushions must be correspondingly introduced into the air gap in a homogeneously distributed manner over the entire length of the pole. This is achieved with the aid of the carrier plate, on which the cushions are provided in a correspondingly distributed manner. The carrier plate in this case provides the structural strength that is required to bring the air cushions to the desired location in the air gap. It has been found to be expedient that the carrier plate is at least approximately as wide and as high as a rotor pole to be released. It has likewise been found to be expedient that the cushions are attached to the carrier plate with the aid of hook-and-loop fasteners. Another expedient and inexpensive way of attaching the cushions to the carrier plate can be realized with the aid of adhesive strips.
The filling of the cushions with gas under pressure takes place with the aid of tubes. These tubes are not represented in the figures. Compressed air, which is generally easily available, comes into consideration in particular as the gas.
However, other gases may also be used. It has been found to be expedient to increase the pressure of the gas in the cushions in stages. In order that the tubes do not unnecessarily hinder the introduction of the device into the air gap, it has been found to be expedient that the tubes are attached to the carrier plate for example with adhesive strips.
The device can in principle be inserted into the air gap in two different alignments.
In the first alignment, the carrier plate faces in the direction of the stator, while the air cushions come to lie in the direction of the rotor pole. In the other alignment, the carrier plate faces in the direction of the rotor pole and the cushions come to lie in the direction of the stator. In principle, both alignments can be used successfully. However, it has been found that the first alignment variant (carrier plate faces in the direction of the stator) is particularly expedient,
The filling of the cushions with gas under pressure takes place with the aid of tubes. These tubes are not represented in the figures. Compressed air, which is generally easily available, comes into consideration in particular as the gas.
However, other gases may also be used. It has been found to be expedient to increase the pressure of the gas in the cushions in stages. In order that the tubes do not unnecessarily hinder the introduction of the device into the air gap, it has been found to be expedient that the tubes are attached to the carrier plate for example with adhesive strips.
The device can in principle be inserted into the air gap in two different alignments.
In the first alignment, the carrier plate faces in the direction of the stator, while the air cushions come to lie in the direction of the rotor pole. In the other alignment, the carrier plate faces in the direction of the rotor pole and the cushions come to lie in the direction of the stator. In principle, both alignments can be used successfully. However, it has been found that the first alignment variant (carrier plate faces in the direction of the stator) is particularly expedient,
4 since in this alignment the carrier plate protects the stator from possible damage.
On the inner side of the stator are the winding slots and the winding bars placed therein. The insulation of the winding bars is particularly sensitive, and a pressure exerted on it could lead to the insulation becoming damaged, and consequently to short-circuits. If the carrier plate lies in the direction of the stator, the carrier plate is supported on the teeth of the laminated stator core that lie between the winding slots and are less sensitive. Protected by the strength of the carrier plate, the winding bars lying in the slots are not subjected to any harmful pressure.
If, on the other hand, the cushions were to lie on the stator side, because of their easy deformability they would push themselves into the slots and thereby also exert a harmful pressure on the winding bars lying therein. If the slots are protected by closure means, which protrude beyond the teeth of the laminated stator core in the direction of the rotor, spacers can also be additionally provided on the teeth, so that the carrier plate is supported on the teeth by way of these spacers and thus cannot press onto the closure means.
Fiber-reinforced plastics, for example so-called fabric-base laminate panels, have been found to be particularly favorable as the material for the carrier plate, because they have a high strength with a small thickness. Also, the use of a plastic ensures that damage to the stator due to instances of impact when the device is introduced into the air gap can be avoided. This is a result of the low hardness of the plastic in comparison with the stator sheets.
In Figure 3, the sequence of the method according to the invention is schematically represented. In the method step denoted by VI., at least one device according to the invention is introduced into the air gap between the stator and a rotor pole to be released. In the method step denoted by V2, the cushions of the device according to the invention are filled with gas under pressure, the pressure of the gas being successively increased until the rotor pole to be released has come away from the rotor hub. In the method step denoted by V3, the device according to the invention is removed from the air gap and, in the method step denoted by V4, the released pole is pulled out of the hub.
Steps Vi to V4 are repeated until all of the poles have been removed. Equally,
On the inner side of the stator are the winding slots and the winding bars placed therein. The insulation of the winding bars is particularly sensitive, and a pressure exerted on it could lead to the insulation becoming damaged, and consequently to short-circuits. If the carrier plate lies in the direction of the stator, the carrier plate is supported on the teeth of the laminated stator core that lie between the winding slots and are less sensitive. Protected by the strength of the carrier plate, the winding bars lying in the slots are not subjected to any harmful pressure.
If, on the other hand, the cushions were to lie on the stator side, because of their easy deformability they would push themselves into the slots and thereby also exert a harmful pressure on the winding bars lying therein. If the slots are protected by closure means, which protrude beyond the teeth of the laminated stator core in the direction of the rotor, spacers can also be additionally provided on the teeth, so that the carrier plate is supported on the teeth by way of these spacers and thus cannot press onto the closure means.
Fiber-reinforced plastics, for example so-called fabric-base laminate panels, have been found to be particularly favorable as the material for the carrier plate, because they have a high strength with a small thickness. Also, the use of a plastic ensures that damage to the stator due to instances of impact when the device is introduced into the air gap can be avoided. This is a result of the low hardness of the plastic in comparison with the stator sheets.
In Figure 3, the sequence of the method according to the invention is schematically represented. In the method step denoted by VI., at least one device according to the invention is introduced into the air gap between the stator and a rotor pole to be released. In the method step denoted by V2, the cushions of the device according to the invention are filled with gas under pressure, the pressure of the gas being successively increased until the rotor pole to be released has come away from the rotor hub. In the method step denoted by V3, the device according to the invention is removed from the air gap and, in the method step denoted by V4, the released pole is pulled out of the hub.
Steps Vi to V4 are repeated until all of the poles have been removed. Equally,
5 only steps Vi to V3 could be repeated until all of the rotor poles are released, and then step V4 is repeated as often as it takes until all of the rotor poles are removed. It is also conceivable that steps V3 and V4 are performed in the opposite sequence.
It has been found to be particularly expedient if an even number of devices according to the invention are used simultaneously in steps V1, V2 and V3. In this case, two devices according to the invention are always introduced at opposite poles and the associated cushions are filled with gas under pressure. In this way, the forces for releasing the poles are introduced symmetrically in relation to the rotor shaft, so that the forces cancel one another out with respect to the rotor shaft. As a result, the bearings of the rotor are not unduly stressed.
It has been found to be particularly expedient if an even number of devices according to the invention are used simultaneously in steps V1, V2 and V3. In this case, two devices according to the invention are always introduced at opposite poles and the associated cushions are filled with gas under pressure. In this way, the forces for releasing the poles are introduced symmetrically in relation to the rotor shaft, so that the forces cancel one another out with respect to the rotor shaft. As a result, the bearings of the rotor are not unduly stressed.
Claims (8)
1. A device for releasing a rotor pole of a large electrical machine from the rotor hub, which in the fitted state is located within the stator, characterized in that the device consists of a carrier plate (1) and at least one cushion (2) that can be filled with gas and is attached to the carrier plate.
2. The device as claimed in claim 1, characterized in that the carrier plate (1) is a fabric-base laminate panel.
3. The device as claimed in either of claims 1 and 2, characterized in that the at least one cushion (2) that can be filled with gas is attached to the carrier plate (1) with the aid of hook-and-loop fasteners or adhesive strips.
4. The device as claimed in one of claims 1 to 3, characterized in that the at least one cushion (2) can be filled with gas with the aid of a tube, the tube being attached leading along the carrier plate (1).
5. The device as claimed in claim 4, characterized in that the at least one tube for filling the at least one cushion (2) is attached to the carrier plate (1) with the aid of adhesive strips.
6. A method for releasing the rotor poles of a large electrical machine from the rotor hub, which in the fitted state is located within the stator, characterized in that, in one method step (V1), at least one device as claimed in one of claims 1 to 5 is introduced into the air gap between the stator and a rotor pole to be released, and in that, in a following method step (V2), the cushions belonging to the device are filled with gas under pressure, the pressure being successively increased until the pole to be released has come away, and in that, in a following method step (V3), the at least one device is removed from the air gap and in that, in a further step (V4), the released pole is pulled out of the rotor hub.
7. The method as claimed in claim 6, characterized in that compressed air is used as the gas.
8. The method as claimed in either of claims 6 and 7, characterized in that in method steps V1, V2 and V3 an even number of devices are respectively used simultaneously, two of the devices in each case being used at opposite rotor poles.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102014207915.2A DE102014207915B3 (en) | 2014-04-28 | 2014-04-28 | Device and method for releasing the rotor poles in an electric machine |
| DE102014207915.2 | 2014-04-28 | ||
| PCT/EP2015/059129 WO2015165865A1 (en) | 2014-04-28 | 2015-04-28 | Device and method for detaching the rotor poles in an electric machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2946942A1 true CA2946942A1 (en) | 2015-11-05 |
| CA2946942C CA2946942C (en) | 2020-08-18 |
Family
ID=53015805
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2946942A Active CA2946942C (en) | 2014-04-28 | 2015-04-28 | Method for releasing the rotor poles in an electrical machine |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US10374495B2 (en) |
| EP (1) | EP3138185B1 (en) |
| CA (1) | CA2946942C (en) |
| DE (1) | DE102014207915B3 (en) |
| WO (1) | WO2015165865A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE950940C (en) * | 1952-10-11 | 1956-10-18 | Gen Electric Canada | Rotor with pronounced poles and removable pole pieces for dynamo-electric machines |
| DE1810501U (en) * | 1958-10-30 | 1960-04-28 | Wilhelm Wiegand | PNEUMATIC LIFTS, IN PARTICULAR JACKS. |
| FR1545301A (en) | 1967-11-24 | 1968-11-08 | Cem Comp Electro Mec | Method and devices for compressing gases |
| US4518151A (en) * | 1982-01-28 | 1985-05-21 | Dill Jr M Reese | Article separator for materials handling |
| DE19520361C2 (en) * | 1995-06-07 | 1999-04-01 | Meyer Rieke Eckhard | Device for lifting and transporting heavy loads |
| JP5717659B2 (en) * | 2012-01-16 | 2015-05-13 | 株式会社東芝 | Salient pole type rotating electric machine and disassembling method thereof |
-
2014
- 2014-04-28 DE DE102014207915.2A patent/DE102014207915B3/en active Active
-
2015
- 2015-04-28 WO PCT/EP2015/059129 patent/WO2015165865A1/en active Application Filing
- 2015-04-28 CA CA2946942A patent/CA2946942C/en active Active
- 2015-04-28 EP EP15719212.1A patent/EP3138185B1/en active Active
-
2016
- 2016-10-28 US US15/337,082 patent/US10374495B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| EP3138185B1 (en) | 2018-04-04 |
| CA2946942C (en) | 2020-08-18 |
| US10374495B2 (en) | 2019-08-06 |
| WO2015165865A1 (en) | 2015-11-05 |
| US20170047825A1 (en) | 2017-02-16 |
| EP3138185A1 (en) | 2017-03-08 |
| DE102014207915B3 (en) | 2015-10-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |
Effective date: 20181113 |